Pyrite
Sulfide · FeS₂ · also: Fool's gold
Pyrite, or “fool’s gold”, is a brassy iron sulfide that forms striking cubes and is famously mistaken for gold.
What is pyrite?
Pyrite is iron disulfide, a metallic brass-yellow mineral that forms remarkably geometric cubes and pyritohedra. Its resemblance to gold earned it the name “fool’s gold”, but it is harder, lighter, brittle and gives a dark streak. Pyrite is common in many geological settings and a favourite for its natural crystal shapes.
Properties
- Chemical formula
- FeS₂
- Category
- Sulfide
- Hardness (Mohs)
- 6–6.5
- Crystal system
- Cubic (isometric)
- Lustre
- Metallic
- Streak
- Greenish-black to brownish-black
- Colour
- Pale brass-yellow
- Cleavage / fracture
- Poor; uneven fracture
How to identify pyrite
- →Pale brass-yellow with a bright metallic lustre.
- →Often forms sharp cubes, sometimes with striated faces.
- →Hardness 6–6.5: too hard to scratch with a knife (unlike gold, which is soft).
- →Greenish-black streak and brittle (real gold is soft, malleable and gives a gold streak).
Where pyrite is found
Pyrite is worldwide. Superb cubes come from Spain (Navajún), and fine specimens from Peru, Italy and the USA.
Pyrite finds on minShelf
Real specimens catalogued by collectors.
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